The Research Center on Cellular Membranes consists of a core facility (protein chemistry laboratory and scanning electron microscope laboratory) and 7 associated research project grants which concern different aspects of membrane biology in normal and diseased cells as indicated below: 1) Under Geometry of membrane proteins, F.M. Richards and collaborators investigate protein distribution in membranes by a variety of penetrant and nonpenetrant labeling reagents; 2) Under Structure and dynamics of membrane glycoproteins, V. Marchesi, L. Stryer, and collaborators are using fluorescent probes to study distances within and rotational motions of glycophorin molecules (among other topics); 3) G.E. Palade, M.G. Farquhar and collaborators work on functional and biogenetic relationships among cellular membranes involved in the secretory pathways (Membrane interactions in eukaryotic cells); 4) D.S. Papermaster investigates synthesis and assembly of rhodopsin in the discs of the outer segments of retinal rods (Immunocytochemical analysis of membrane biosynthesis); 5) Under Hormone receptors in normal and hypertensive vasculature, J.D. Jamieson and collaborators work on photoaffinity labeling of angiotensin II receptors on vascular smooth muscle; 6) Under Molecular mechanisms of action of cholera enterotoxin M.W. Bitensky continues his work on the effect of this toxin on adenylate cyclase; and finally 7) Under Membrane proteins and tumor specific antigens V. Marchesi and collaborators are finishing the work on the primary structure of glycophorin and are beginning to sequence the spectrins.